Method of manufacturing a semiconductor device including proton irradiation and semiconductor device including charge compensation structure
A method of manufacturing a semiconductor device includes forming a charge compensation device structure in a semiconductor substrate. The method further includes measuring a value of an electric characteristic related to the charge compensation device. At least one of proton irradiation and annealing parameters are adjusted based on the measured value. Based on the at least one of the adjusted proton irradiation and annealing parameters the semiconductor substrate is irradiated with protons, and thereafter, the semiconductor substrate is annealed.
Latest Infineon Technologies AG Patents:
Semiconductor devices known as charge compensation or super junction (SJ) semiconductor devices, e.g. SJ insulated gate field effect transistors (SJ IGFETs) are based on mutual space charge compensation of n- and p-doped regions in a semiconductor substrate allowing for an improved trade-off between low area-specific on-state resistance Ron×A and high breakdown voltage Vbr between load terminals such as source and drain. Performance of charge compensation or SJ semiconductor devices depends upon a lateral or horizontal charge balance between the n-doped and p-doped regions. Process tolerances lead to deviations of a target charge balance that may result in an undesirable decrease of device performance such as a reduction in a source to drain breakdown voltage.
It is desirable to improve the trade-off between the area-specific on-state resistance and the blocking voltage of a semiconductor device and to reduce the impact of process tolerances on this trade-off.
SUMMARYAn embodiment refers to a method of manufacturing a semiconductor device. A charge compensation device structure is formed in a semiconductor substrate. A value of an electric characteristic related to the charge compensation device is measured. At least one of proton irradiation and annealing parameters are adjusted based on the measured value. Based on the at least one of the adjusted proton irradiation and annealing parameters the semiconductor substrate is irradiated with protons, and thereafter, the semiconductor substrate is annealed.
According to an embodiment of a semiconductor device, the semiconductor device comprises a charge compensation structure including p-doped and n-doped regions arranged consecutively in a semiconductor substrate along a lateral direction. The semiconductor device further includes a first dopant species dominating a doping profile of the p-doped regions and a second dopant species dominating a doping profile of the n-doped regions. The semiconductor device further includes hydrogen-related donors in the p-doped and n-doped regions. The hydrogen-related donors differ from the second dopant species.
According to another embodiment of a semiconductor device, the semiconductor device comprises a charge compensation structure including p-doped and n-doped regions arranged consecutively in a semiconductor substrate along a lateral direction. The semiconductor device further includes an n-doped field stop zone between the charge compensation structure and a second side of the semiconductor substrate. Within a range of the n-doped field stop zone, an end-of-range peak profile of hydrogen-related donors is smaller than a profile of another n-type dopant species of the n-doped field stop zone.
Those skilled in the art will recognize additional features and advantages upon reading the following detailed description and on viewing the accompanying drawings.
The accompanying drawings are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification. The drawings illustrate the embodiments of the present disclosure and together with the description serve to explain principles of the disclosure. Other embodiments and intended advantages will be readily appreciated as they become better understood by reference to the following detailed description.
In the following detailed description, reference is made to the accompanying drawings, which form a part hereof, and in which are shown by way of illustrations specific embodiments in which the disclosure may be practiced. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. For example, features illustrated or described for one embodiment can be used on or in conjunction with other embodiments to yield yet a further embodiment. It is intended that the present disclosure includes such modifications and variations. The examples are described using specific language that should not be construed as limiting the scope of the appending claims. The drawings are not scaled and are for illustrative purposes only. For clarity, the same elements have been designated by corresponding references in the different drawings if not stated otherwise.
The terms “having”, “containing”, “including”, “comprising” and the like are open and the terms indicate the presence of stated structures, elements or features but not preclude the presence of additional elements or features. The articles “a”, “an” and “the” are intended to include the plural as well as the singular, unless the context clearly indicates otherwise.
The term “electrically connected” describes a permanent low-ohmic connection between electrically connected elements, for example a direct contact between the concerned elements or a low-ohmic connection via a metal and/or highly doped semiconductor. The term “electrically coupled” includes that one or more intervening element(s) adapted for signal transmission may exist between the electrically coupled elements, for example elements that temporarily provide a low-ohmic connection in a first state and a high-ohmic electric decoupling in a second state.
The Figures illustrate relative doping concentrations by indicating “−” or “+” next to the doping type “n” or “p”. For example, “n−” means a doping concentration that is lower than the doping concentration of an “n”-doping region while an “n+”-doping region has a higher doping concentration than an “n”-doping region. Doping regions of the same relative doping concentration do not necessarily have the same absolute doping concentration. For example, two different “n”-doping regions may have the same or different absolute doping concentrations.
The method comprises forming a charge compensation device structure in a semiconductor substrate. In the schematic top view of
The vertical SJ NFET illustrated in
Referring to the schematic view illustrated in
The electric characteristic αi characterizes a charge balance of the charge compensation device structure with respect to a target value. Since the charge balance constitutes a reference parameter for correction of an overall charge in the n- and p-doped regions 111, 112, precision of correction can be improved with respect to a correction process having the overall charge in the n- and p-doped regions 111, 112 as the reference parameter for correction.
Based on the measured value of the electric characteristic αi related to the charge compensation device structure, proton irradiation and/or annealing parameters are adjusted. According to an embodiment, at least one of number, dose and energy of proton irradiation are adjusted based on the measured value of the electric characteristic αi. According to an embodiment, the adjusted proton irradiation parameters include an implantation dose in a range of 2×1014 cm−2 and 8×1014 cm−2 and an implantation energy in a range of 1.0 MeV and 3.0 MeV. According to an embodiment, the adjusted proton irradiation parameters are configured to shift a charge balance of the charge compensation device structure based on the measured value of the electric characteristic towards or to a target charge balance of the charge compensation device structure. Irradiation of the semiconductor substrate with the adjusted proton irradiation parameters will generate hydrogen-related donors leading to an increase of n-doping in both the p- and n-doped regions 111, 112 of the charge compensation device structure.
Referring to the schematic view of
Referring to the schematic view of
The doping is effected predominantly in the so-called end-of-range region of the proton implantation, and to a lesser extent in the region radiated through. Annealing of the substrate 105 leads to diffusion of the hydrogen into the irradiated area and may also reach the surface radiated through whereby the formation of complexes comprising the hydrogen atoms and the irradiation-induced defects like e.g. vacancies results in the creation of donors, e.g. so-called hydrogen-related donors in this region.
Since at least one of the proton irradiation and annealing parameters are based on the measured value of the electric characteristic αi related to the charge compensation device, a precise correction process of charge balance in the n-doped and p-doped regions 111, 112 of the charge compensation device structure can be carried out with respect to an overall depth of a voltage absorbing volume of the charge compensation device structure, e.g. with respect to an overall depth of a drift zone of the charge compensation device. According to an embodiment, the hydrogen-related donors extend over at least 30% of a vertical extension of a drift zone between a first side and a second side of the semiconductor substrate. According to another embodiment, a concentration of the hydrogen-related donors is in a range of 5×1013 cm−3 and 8×1014 cm−3.
As is indicated by a dashed line 141 between
By appropriately adjusting parameters such as proton irradiation dose, proton irradiation energy, annealing temperature and annealing duration, the peak areas 1530, 1531, 1532, 1533 may be adjusted with respect to peak height, broadening, depth of peak, overlap with neighboring peak areas, for example.
According to other embodiments, proton irradiation may be carried out from opposite sides such as the first and second sides 120, 128 illustrated in
The illustrated dopant profile relates to the n-type region 111. The n-type region 111 includes a first concentration N1 of n-type dopants. The dopant concentration N1 may be formed by in-situ doping while manufacturing the charge compensation device structure, e.g. in-situ doping during epitaxial growth or deposition. In addition or as an alternative, the concentration N1 may be formed by ion implantation of n-type dopants, e.g. when manufacturing the charge compensation device structure by a so-called multiple epitaxy technology, for example. According to an embodiment, a dopant species of the dopant concentration N1 may include one or more of phosphor (P), antimony (Sb) and arsenic (As). A profile of the first concentration N1 of the n-type dopants may be almost constant or include an undulation which may be caused by multiple ion implantation processes of n-type dopants in the multiple epitaxy technology.
In addition to the first concentration N1 of the n-type dopants the n-type region 111 further includes, according to an embodiment, a second concentration N20 of hydrogen-related donors which is almost homogeneous and formed by a single proton implantation as illustrated, for example, in
The second concentration N20 may be formed in conjunction with correcting a charge balance in the charge compensation device structure as illustrated in
According to another embodiment, a second concentration N21 of hydrogen-related donors may include multiple peaks due to overlapping profiles of hydrogen-related donors caused by multiple proton irradiations at different energies as illustrated in
Similar to second concentration N20 illustrated in
According to another embodiment, the p-type region 112 further includes the second concentration N21 of hydrogen-related donors having multiple peaks caused by overlapping profiles of hydrogen-related donors resulting from multiple proton irradiations at different energies as illustrated in
According to an embodiment, end-of-range peaks of the first concentrations N20, N21 of hydrogen-related donors are located within the optional field stop zone 114.
The method of charge balance correction illustrated in
The method may also be applied to other device layouts. One example of another device layout is a lateral charge compensation or SJ FET 500 illustrate in
A planar gate structure including a gate dielectric 524 and a gate electrode 525 is arranged on the p-well 517 between the n+-type source region 522 and the n-type and p-type regions 511, 512. A gate electrode contact 546 is electrically coupled to the gate electrode 525. In the illustrated embodiment of
Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that this invention be limited only by the claims and the equivalents thereof.
Claims
1. A method of manufacturing a semiconductor device, the method comprising:
- forming a charge compensation device structure in a semiconductor substrate;
- measuring a value of an electric characteristic related to the charge compensation device;
- adjusting at least one of proton irradiation and annealing parameters based on the measured value;
- irradiating the semiconductor substrate with protons and thereafter;
- annealing the semiconductor substrate based on the at least one of the adjusted proton irradiation and annealing parameters.
2. The method of claim 1, wherein measuring the value of the electric characteristic related to the charge compensation device includes measuring an electric breakdown voltage.
3. The method of claim 2, wherein the electric breakdown voltage is measured with respect to a test structure in the semiconductor substrate.
4. The method of claim 2, wherein the electric breakdown voltage is based on measuring electric breakdown voltages with respect to a plurality of test structures across the semiconductor substrate.
5. The method of claim 1, wherein the annealing the semiconductor substrate is carried out in a temperature range of 350° C. and 550° C. for a duration between 30 minutes and 10 hours.
6. The method of claim 1, wherein the irradiating the semiconductor substrate with protons based on the at least one of the adjusted proton irradiation and annealing parameters is carried out from a first side of the semiconductor substrate where a control terminal of the charge compensation device structure is located.
7. The method of claim 1, wherein the irradiating the semiconductor substrate with protons based on the at least one of the adjusted irradiation and annealing parameters is carried out once.
8. The method of claim 7, wherein the irradiating the semiconductor substrate with protons based on the adjusted irradiation parameters includes an implantation dose in a range of 2×1014 cm−2 and 8×1014 cm−2, an implantation energy in a range of 1.0 MeV and 3.0 MeV and annealing temperatures in a range of 380° C. and 500° C.
9. The method of claim 7, wherein the irradiating the semiconductor substrate with protons based on the at least one of the adjusted irradiation and annealing parameters places an end-of-range peak within a field stop zone.
10. The method of claim 1, wherein the irradiating the semiconductor substrate with protons based on the at least one of the adjusted irradiation and annealing parameters is carried out multiple times at different implantation energies and/or implantation doses.
11. The method of claim 10, wherein the irradiating the semiconductor substrate with protons based on the at least one of the adjusted irradiation and annealing parameters includes implantation doses in a range of 5×1013 cm−2 and 2×1014 cm−2, and annealing temperatures in a range of 380° C. and 430° C.
12. The method of claim 10, wherein the irradiating the semiconductor substrate with protons based on the adjusted at least one of the adjusted irradiation and annealing parameters is carried out between two and six times.
13. The method of claim 1, further comprising, after proton irradiation of the semiconductor substrate,
- forming a metallization at a first side of the semiconductor substrate where a control terminal of the charge compensation device structure is located; and thereafter
- annealing the semiconductor substrate in a temperature range of 350° C. and 550° C.
14. The method of claim 1, further comprising:
- forming a metallization at a first side of the semiconductor substrate where a control terminal of the charge compensation device structure is located; thereafter
- irradiating the semiconductor substrate with protons; and thereafter
- annealing the semiconductor substrate in a temperature range of 350° C. and 550° C.
15. The method of claim 1, further comprising annealing the semiconductor substrate with a thermal budget configured to deactivate at least a part of donors generated by proton irradiation and annealing.
16. A semiconductor device, comprising:
- a charge compensation structure including p-doped and n-doped regions arranged consecutively in a semiconductor substrate along a lateral direction;
- a first dopant species dominating a doping profile of the p-doped regions;
- a second dopant species dominating a doping profile of the n-doped regions; and
- hydrogen-related donors in the p-doped and n-doped regions, wherein the hydrogen-related donors differ from the second dopant species.
17. The semiconductor device of claim 16, further comprising:
- an n-doped field stop zone between the charge compensation structure and a second side of the semiconductor substrate, and
- wherein, within a range of the n-doped field stop zone,
- an end-of-range peak profile of hydrogen-related donors is smaller than a profile of another n-type dopant species of the n-doped field stop zone.
18. The semiconductor device of claim 16, wherein the hydrogen-related donors extend over at least 30% of a vertical extension of a drift zone between a first side and a second side of the semiconductor substrate.
19. The semiconductor device of claim 16, wherein a concentration of the hydrogen-related donors is in a range of 5×1013 cm−3 and 8×1014 cm−3.
20. A semiconductor device, comprising:
- a charge compensation structure including p-doped and n-doped regions arranged consecutively in a semiconductor substrate along a lateral direction; and
- an n-doped field stop zone between the charge compensation structure and a second side of the semiconductor substrate,
- wherein, within a range of the n-doped field stop zone,
- an end-of-range peak profile of hydrogen-related donors is smaller than a profile of another n-type dopant species of the n-doped field stop zone.
6566201 | May 20, 2003 | Blanchard |
8367532 | February 5, 2013 | Mauder et al. |
8421196 | April 16, 2013 | Weber et al. |
20030011039 | January 16, 2003 | Ahlers et al. |
2007085387 | August 2007 | WO |
Type: Grant
Filed: Dec 4, 2013
Date of Patent: Apr 21, 2015
Assignee: Infineon Technologies AG (Neubiberg)
Inventors: Hans-Joachim Schulze (Taufkirchen), Hans Weber (Bayerisch Gmain), Werner Schustereder (Villach), Wolfgang Jantscher (Villach), Helmut Strack (Munich)
Primary Examiner: Kyoung Lee
Application Number: 14/096,804
International Classification: H01L 29/66 (20060101); H01L 29/06 (20060101); H01L 21/66 (20060101); H01L 21/265 (20060101); H01L 29/78 (20060101);